Three Distinct Mechanisms Generate Oxygen Free Radicals in Neurons and Contribute to Cell Death during Anoxia and Reoxygenation

By A. Abramov, A. Scorziello, M. Duchen. Journal of Neuroscience, 2007

663 citations recorded by the source corpus.

Ischemia is a major cause of brain damage, and patient management is complicated by the paradoxical injury that results from reoxygenation. We have now explored the generation of reactive oxygen species (ROS) in hippocampal and cortical neurons in culture in response to oxygen and glucose deprivation or metabolic inhibition and reoxygenation. Fluorescence microscopy was used to measure the rate of ROS generation using hydroethidine, dicarboxyfluorescein diacetate, or MitoSOX. ROS generation was correlated with changing mitochondrial potential (rhodamine 123), [Ca2+]c (fluo-4, fura-2, or Indo-1), or ATP consumption, indicated by increased [Mg2+]c. We found that three distinct mechanisms contribute to neuronal injury by generating ROS and oxidative stress, each operating at a different stage of ischemia and reperfusion. In response to hypoxia, mitochondria generate an initial burst of ROS, which is curtailed once mitochondria depolarize or prevented by previous depolarization with uncoupler. A second phase of ROS generation that followed after a delay was blocked by the xanthine oxidase (XO) inhibitor oxypurinol. This phase correlated with a rise in [Mg2+]c, suggesting XO activation by accumulating products of ATP consumption. A third phase of ROS generation appeared at reoxygenation. This was blocked by NADPH oxidase inhibitors and was absent in cells from gp91phox−/− knock-out mice. It was Ca2+ dependent, suggesting activation by increased [Ca2+]c during anoxia, itself partly attributable to glutamate release. Inhibition of either the NADPH oxidase or XO was significantly neuroprotective. Thus, oxidative stress contributes to cell death over and above the injury attributable to energy deprivation.

Subfields: Biophysics, Molecular Biology, Neurology

View Paper: https://www.semanticscholar.org/paper/914c090fd3082be9441620cfd5f3568f9266ba90

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Biophysics

In Molecular Biology

In Neurology

Citations in the corpus

Role of mitochondrial ROS in the brain: from physiology to neurodegeneration (2018, background): “[16] Abramov AY, Scorziello A, & Duchen MR (2007) Three distinct mechanisms generate oxygen free radicals in neurons and contribute to cell death during anoxia and reoxygenation.”
NAD+/NADH and NADP+/NADPH in Cellular Functions and Cell Death: Regulation and Biological Consequences (2008, neutral): “For example, it was reported that the NADPH oxidase activation in astrocytes mediates -amyloid-induced neuronal death (1); NADPH oxidase also plays a key role in the ROS generation in the neurons that are exposed to oxygen—glucose deprivation—-an in vitro model for brain ischemia (3); and genetic or”
Oxidative Stress in Ischemic Brain Damage: Mechanisms of Cell Death and Potential Molecular Targets for Neuroprotection (2011, background): “In OGD-treated hippocampal and cortical neurons, three distinct mechanisms contributed to generating oxygen radicals and causing oxidative injury, with each mechanism operating at a different stage of ischemia and reperfusion (1).”
Ischemia/Reperfusion (2016, neutral): “to a XO-dependent second phase, while enhanced NADPH oxidase activity predominates as a ROS source upon reoxygenation (4).”
Cell Biology of Ischemia/Reperfusion Injury (2012, background): “Another recent study of ROS-induced apoptosis in cultured neurons exposed to anoxia–reoxygenation reported a clear temporal sequence of ROS generation, beginning with a transient increase in mitochondrial production during hypoxia, progressing to a second phase dependent on XO, and finally a third p”
Mechanism of Oxidative Stress in Neurodegeneration (2012, background): “Inhibition of neuronal respiration by oxygen deprivation or chemical ischemia leads to a significant increase in the generation of ROS in mitochondria [94].”
The Role of Oxidative Stress in Neurodegenerative Diseases (2015, background): “XO and xanthine dehydrogenase (XDH) are inter-convertible forms of xanthine oxidoreductase [32].”
Reperfusion injury and reactive oxygen species: The evolution of a concept (2015, background): “It has been demonstrated that purified cultured cell populations, including endothelial cells [244], cardiac myocytes [245] and neurons [246] exposed to simulated I/R in vitro exhibit tissue injuryrelated responses that are dependent on Nox activity.”
Molecular Mechanisms of Ischemia-Reperfusion Injury in Brain: Pivotal Role of the Mitochondrial Membrane Potential in Reactive Oxygen Species Generation (2012, background): “Ischemia has been found to cause depolarization of ΔΨm following simulated ischemia in vitro [79] and in vivo during experimental stroke [80].”
A Unifying Mechanism for Mitochondrial Superoxide Production during Ischemia-Reperfusion Injury. (2016, background): “However, activation of these processes seems to occur after the initial burst of mitochondrial ROS and their role in the proximal cascade of reperfusion pathology is unclear, suggesting that non-mitochondrial ROS contributes to secondary tissue damage and subsequent inflammation (Abramov et al., 200”
Mitochondrial reactive oxygen species (ROS) and ROS-induced ROS release. (2014, background): “Three potential sources of ROS have been proposed to be responsible for this release: mitochondrial complex I, xanthine oxidase, and NADPH oxidase (2, 471, 491).”